Synchronizing unit



April 25, 1950 Y L. M. POTTS 2,505,722

SYNCHRONIZING UNIT Filed June 4, 1947 2? FIG. 3

TORNEY Patented Apr. 25, 1950 UNITED STATES PATENT OFFICE SYNCHRONIZING UNIT Application June 4, 1947, Serial No. 752,514

1 Claim.

This invention pertains to telegraph systems and more particularly to automatic synchronizing means therefor.

The primary object of the invention is to provide in a system comprising a plurality of primary units and a plurality of second units, facilities whereby any secondary unit, when connected to a primary unit, will automatically come into synchronism with the primary unit.

Another object of the invention is to provide primary and secondary stations having instrumentalities at their respective stations so that when any secondary station is plugged into any primary station, automatic synchronization between the connected stations will result.

More specifically, the invention contemplates a plurality of master control units and a plurality of plug-in units, said master units having individual motor speed control means, and synchronizing means comprising cooperating elements in said master units and said plug-in units, whereby any of said plug-in units when connected to any of said master units will be maintained in synchronism therewith.

A more complete understanding of the invention may be had from the following description taken in conjunction with the accompanying drawing wherein:

Fig. 1 is a schematic view showing the electrical circuit arrangement at the master control station;

Fig. 2 is a schematic electrical circuit diagram of the arrangement at the controlled station;

Fig. 3 is a block diagram of a second master control station; and

Fig. 4 is a block diagram of a second controlled station.

Having reference to the drawing, there is shown in Fig. 1 a schematic circuit arrangement for a primary or master control station II including a signal distributor unit I2; for example, a tape transmitter, combination transmitter and printer or a multiplex distributor. In the station N there is provided a motor I3 having an armature I4, and on the shaft I5 of the motor I3 are mounted two synchronizing commutators I6 and I1. Shaft I5 also extends into and is operatively connected to the mechanism in unit l2.

The field I8 of motor I3 has in series therewith a rheostat IS, the shaft 2| of which projects through the station unit II and terminates in a knob 22 by the manipulation of which the rheostat I9 is regulated. It will be observed that in the embodiment illustrated, motor I3 isa shunt motor and is operated from a direct current source 23 through a knife switch 24. In series with the armature I4 of the motor I3 is a resistance 25. It is assumed that unit II is a synchronous distributor of some sort, and the speed thereof is controlled by a vibrating contact arm 25 of a tuning fork (not shown) which may be analogous to contact 44 of the tuning fork control mechanisms D or H shown in U. S. Patent No. 1,754,316 granted to H. L. Krum.

The synchronous circuit is similar to that shown and described in U. S. Patent No. 726,750 issued to L. M. Potts. In said patent, however, series wound motors are disclosed while in the embodiment shown herein, shunt wound motors are disclosed. The station 21 (Fig. 3) is identical to station II and hence is indicated only in box outline with knob 28 and plugs 29 and 3|. On shaft 2| is mounted a second rheostat 32 which is like rheostat I9 assuming that all the motors and circuits are alike and all of the units have approximately the same load. If the motors have different loads it may be necessary to make a difference in the two rheostats I9 and 32 to compensate for the difierence of load. The apparatus at station I I is synchronized in the usual manner at whatever speed may be desired, and the knob 22 is turned in order to regulate the rheostat I9 so that the motor will run at such a speed that when synchronism is attained it will be operating in about the middle of its range. The various connections of the motor unit I3 are brought out to a plug connection 33. Similarly, the connections for the telegraph unit I2 are brought out to a plug connection 34.

An auxiliary station 35 is shown in Fig. 2 which includes a motor unit 36 and a telegraph apparatus 31 such as a receiving unit (eithera reperforator, printer, etc). Unit 36 has a motor armature 38, and in series therewith is a resistance 39 which functions in the same manner as resistance 25 of unit I3. Mounted on the shaft 4| of the motor unit 36 is a synchronizing commutator 42, which shaft 4| also carries the armature 38. Shaft 4| also extends into and is operatively connected to the mechanism in the telegraph unit or apparatus 31. The resistance 39 is so chosen that it is the proper value for properly controlling the motor speed, and will be of the same value as resistance 25. Connections from the motor unit 36 of station 35 terminate in a plug connector 43, and the connections from the unit 31 terminate in a plug connection 44. The field of motor 36 has in series therewith over conductors 46 and 41 (through plug connections 33 and 43) the rheostat 32 con- 3 tained in station II (Fig. 1). Motor 36 is also a shunt wound motor and is operated from a direct current source 48 through a knife switch 49.

In the operation of the system according to the invention, the motor I3 is brought up to the proper speed by properly adjusting the tuning fork, exemplified by the vibrating contact arm 26, in well known manner. Associated electrically with the contact arm 26 is the synthronizing commutator or circuit changer I6 which is composed of two metallic sections having interlocking segments and brushes 5|, 52, and 53 which are disposed upon the face of the circuit changer I6, as shown, so that as the circuit changer rotates electrical connection will be made between'the central brush 52 and first one and then the other of the contacts 54 and 55 of the tuning fork alternately. The central brush -52 is connected over conductor 56 and through adjustable resistance 25 to the armature I4, so that when the circuit changer I6 is rotating in synchronism with the vibrations of arm 26, energizing current for the motor I3 is flowing from positive side of current source 23, through switch 24 (now closed), over conductor 51, through armature I4, through resistance 25, over conductor 56, through central brush 52, then through left half of commutator I6, over brush 5 I, through contact 54, over arm 26, over conductors 58 and 59, through switch 24 to negative side of current source 23. In synchronism, the circuit will alternately change to include the right half of commutator I6 to complete the circuit between brushes 52 and 53 and through contact 55 associated with the tuning fork contact arm 26. So long as the commutator I6 and arm 26 are operating in phase to maintain brushes 5I and 52 and contact 54 in closed electrical circuit, and brushes 52 and 53 and contact 55 in closed electrical circuit alternately, current will be supplied to armature l4. However, if synchronism is disturbed, these circuits will be opened and the motor I3 will be slowed down until synchronism is again attained.

To achieve the object of the present invention, a second commutator or circuit changer I1 is mounted on the shaft I5 and comprises two metallic sections having interlocking segments and brushes 6|, 62, and 63 disposed on the face of the circuit changer to make circuit connections similar to circuit changer I6 and its brushes. Brush H is adapted (under conditions hereinafter described) to be connected over conductors 64 and 65 to a brush 66 disposed on the face of the commutator 42 at station 35. Likewise, brush 63 is adapted to be connected over conductors 61 and 68 to a brush 69 associated with commutator 42. The center brush 62, at station II, is adapted to be connected over conductors H and 12 to the negative side of source of current 48 at station 35. The station 13 (Fig. 4) is identical to station 35 and hence is indicated only in box outline with plugs 14 and 15.

When the unit I3 at station I I is synchronized, the knob 22 is moved until conditions are correct for synchronizing at the chosen speed. It is observed then that the rheostat 32 will be adjusted in a similar manner, and assuming that plug 34 is connected to jack 44, and the plug elements 33 and 43 are connected, the motor 36 at station 35 will be brought into synchronism with motor I3 at station 'II automatically in the following manner.

Assuming that the motor I3 has been adjusted to operate the telegraph apparatus I2 at a predetermined speed; for example, 75 words per minute, and the afore-mentioned connections between stations II and 35 have then been made, the commutator I1 will be rotating at the same speed as commutator I6. Let it be assumed also that the commutators I1 and 42 are rotating in synchronism and have attained a constant state with the phase relation of the brushes 6 I-62-63 and 66-16-69, as indicated. When the brushes occupy this relation, a circuit for motor 36 is completed from positive side of current source 48, through switch 49 (now closed) over conductor 84, through armature 38, over resistance 39 to contact 18, over conductor 19, through brush 16, over segment 8|, through brush 66, over conductors 65 and 64, through brush 6|, over segment 82, through brush 62, over conductors 1|, 12, and 83, through switch 49 to negative side of current source 48. Also, a, circuit is alternately completed from positive side of current source 48, through switch 49, over conductor 84, through armature 38, over resistance 39 to contact 18, over conductor 19, through brush 16, over segment 85, through brush 69, over conductors 68 and 61, through brush 63, over segment 86, through brush 62, over conductors II, 12, and 83, through switch 49 to negative side of current source 48. Under this condition of operation current will flow through the armature of the motor 36 as well as the field 45 thereof.

However, if the motor 36 should increase its speed, the circuits just described would be disturbed between the brushes 66-18, 69-16, 6I-62, or 62-63. That is, segments 81 and 82 may not be spanning brushes 65-16 and 6I-62,

, respectively, simultaneously. Nor will segments 85 and 86 span brushes 69-16 and 62-63 simultaneously. Therefore, if segment 8I spans brushes 66-16 when segment 86 spans brushes 62-63, or if segment 85 spans brushes 69-16 when seg ment 82 spans brushes 6I-62, then no current will flow through the armature 38 and accordingly the armature current will be diminished. The speed of the motor 36 will thereby be diminished until synchonism is again attained. If the commutators I1 and 42 are not rotating in synchronism when the plug elements 33 and 43 are connected, the motor 36 will come into synchronism automatically, and the resistance will be exactly right for synchronizing unit 35 at this speed.

When the plug elements 34 and 44 are connected, the line circuit for the telegraph elements is completed from battery 81, through the winding of the selector magnet 88 of unit I2, through transmitting contacts 89, over conductors 9I and 92, through the winding of selector magnet 93 of the unit 31, over conductors 94 and 95 to battery 81. Since the motors I3 and 36 are brought into synchronism and maintained thus, it is assured that the telegraph units I2 and 31 will operate in proper phase through the respective shafts I5 and 4|.

Unit 21 may be operated at quite a different speed from unit II so that the knob 28 will be in a different position from knob 22. If the unit 35 is now connected to unit 21, the proper adjustment will now exist in the rheostat of 21 corresponding to rheostat 32 for synchronizing with the proper adjustment. For example, unit 21 may have been adjusted to operate at a speed of 60 words per minute, and when the connections between stations or units 21 and 35 have been made, unit 35 will be controlled to operate at the speed of 60 words per minute. Unit 13 is just like unit 35 and may be connected to either unit II or unit 21.

There may be a large number of both kinds of units |l-21 and 35-13. Units 35 and 13 may also be of different kinds in its particular class. One may be a perforator, another might be a transmitter or it might be a tape or page printer, or some other sort of receiving device. The knob 22 may be any knob which is used for adjustment for different speeds of operation, and the rheostat may be in other parts of the circuit than in the field circuit.

Although the drawing discloses a shunt wound motor, it is understood that the invention is not confined to such a specific application, as the principle is applicable to the synohronism of series and compound wound motors as well as to shunt motors. Accordingly, it is contemplated that some changes may be made in the relative arrangement of the parts without departing from the spirit and scope of the invention.

What is claimed is:

In a telegraph system, a primary control sta tion unit, signal generating means associated with said primary station unit, a motor in said primary station unit, a first rheostat for controlling the field current in said motor, motor speed control means comprising a first synchronizing commutator and a tuning fork operated contact adapted to cooperate with said commutator to maintain said motor at a predetermined speed, a second synchronizing commutator in said primary station unit rotatable with said first commutator, a second rheostat in said primary station unit adjustably associated with said first rheostat, a secondary station unit, signal receiving means associated with said secondary station unit and responsive to signals generated at said primary station unit, a motor in said secondary station unit, said second rheostat effective under predetermined operating conditions to control the field current of said secondary station motor, motor speed control means in said secondary station unit comprising a third synchronizing commutator, and electrical circuit means including plug connection elements associated with said primary and secondary station units for efiectuating inter-c011 trol between said station units, whereby said primary and secondary station units are maintained in synchronism under the control of said second and third synchronizing commutators following the operative engagement of said plug connection elements.

MARTHA W. C. POTTS, Emecutm'a: under the Last Will and Testament of Louis M. Potts, Deceased.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,895,112 Vernam Jan. 24, 1933 2,173,335 Kinkhead M Sept. 19, 1939 2,246,284 Artzt June 17, 1941 2,249,435 Potts July 15, 1941 2,265,339 Blanton Dec. 9, 1941 2,374,704 Ridings May 5, 1945 2,383,360 Artzt Aug. 21, 1945 OTHER REFERENCES TM 11-486, War Dept., April 25, 1945, See. 337, pages 91-92.

- and that the said Letters Patent should be read with these corrections therein that Certificate of Correction Patent No. 2,505,722 April 25, 1950 LOUIS M. POTTS, DECEASED, BY MARTHA W. (J. POTTS, EXEOUTRIX It is hereby certified that errors appear in the printed specification of the above numbered patent requiring correction as follows:

Column 2, line 9, for Patent N 0. 1,754,316 read Patent No. 1,764,316; column 3, line 9, for synthronizing read synchrom'amg; column 4, line 44, for synchonism read synchromsm the same may conform to the record of the case in the P atent Office. Signed and sealed this 8th day of August, A. D. 1950.

[SEAL] THOMAS F. MURPHY,

Assistant Gammz'ssz'oner of Patents.

Certificate of Correction Patent No. 2,505,722 April 25, 1950 LOUIS M. POTTS, DECEASED, BY MARTHA W. C. POTTS, EXEOUTRIX It is hereby certified that errors appear in the printed specification of the above numbered patent requiring correction as follows:

Column 2, line 9, for Patent No. 1,754,316 read Patent No. 1,764,316; column 3, line 9, for synthronizing read synchronizing; column 4, hne 44, for synchonism reed synchronism;

and that the said Letters Patent should be read with these corrections therein that the some may conform to the record of the case in the Patent Ofiice.

Signed and sealed this 8th day of August, A. D. 1950.

[SEAL] THOMAS F. MURPHY,

Assistant Commissioner of Patents.

Certificate of Correction Patent N 0. 2,505,722 April 25, 1950 numbered patent requiring correctwn as follows Column 2, line 9, for Patent No. 1,7 54,316 read Patent No. 1,764,816; column 3, hne 9, for synthronizing read synchronizing; column 4, line 44, for synchonism reed synchronism;

- and that the said Letters Patent should be read with these corrections therein that the same may conform to the record of the case in the Patent Otfice.

Signed and sealed this 8th day of August, A. D. 1950.

THOMAS F. MURPHY,

Assistant Commissioner of Patents. 

